GPT-5.1 Codex

OpenAI's GPT-5.1 variant optimized for agentic coding in Codex workflows.

Agentic CodingCodex OptimizedSnapshot Model

Context Window

400,000

GPT-5.1 Codex

Max Output

128,000

1M tokens

Input

$1.25

Output

$10

Model Codegpt-5.1-codex

Playground

Model Code

gpt-5.1-codex

Enter your prompt here...

Output

No output yet

Pricing

Plan	Context Window	Max Output	Input	Output	Cache Write	Cache Read
GPT-5.1 Codex	400,000	128,000	$1.25	$10	-	$0.125

Official OpenAI pricing for GPT-5.1-Codex.

Cached input pricing applies to reused prompt tokens.

Cache read or cached input pricing applies to reused prompt tokens.

README

GPT-5.1 Codex is a coding-specialized GPT-5.1 model tuned for long-horizon software tasks, agentic implementation, and robust coding reliability in Codex-style environments.

OpenAI describes GPT-5.1-Codex as a GPT-5.1 variant optimized for coding and available as regularly updated snapshots.
It is designed for complex implementation tasks where code quality, tool use, and longer task horizons matter.
Compared with general-purpose models, GPT-5.1 Codex is positioned for software workflows and agentic development loops.

API

Use the API docs for request format, parameters, and integration details.

OpenAI's GPT-5.1 variant optimized for agentic coding in Codex workflows.

Model Code

gpt-5.1-codex

View API Docs

API

Endpoint

POST /v1/responses

Authentication

Authorization: Bearer YOUR_REACH_API_KEY
Content-Type: application/json

Example

curl -X POST "https://direct.reachapi.ai/v1/responses" \
  -H "Authorization: Bearer YOUR_REACH_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "YOUR_MODEL_ID",
    "input": "Introduce ReachAPI in one sentence.",
    "temperature": 0.2
  }'

Related Models

Other models from the same vendor

GPT-5.6 Luna

OpenAI's GPT-5.6 model for efficient, cost-sensitive, high-volume workloads.

GPT-5.6 Sol

OpenAI's GPT-5.6 flagship model for the most demanding production reasoning, coding, and agent workflows.

GPT-5.6 Terra

OpenAI's GPT-5.6 model for strong intelligence with a balanced cost profile.

GPT-5.5

OpenAI's newest frontier model for the most complex coding, reasoning, and professional workflows.

GPT-5.4

OpenAI's frontier model for complex professional, coding, and agentic work at scale.

GPT-5.4 Mini

OpenAI's strongest mini model for coding, computer use, and high-volume agent tasks.

GPT-5.3 Codex

OpenAI's most capable agentic coding model to date.

GPT-5.2

OpenAI's stronger GPT-5-family model for professional, general-purpose, and agentic work.

GPT-5.1

OpenAI's flagship model for coding and agentic tasks with configurable reasoning.

GPT-5

OpenAI's previous intelligent reasoning model for coding and agentic tasks.

GPT-5 Mini

OpenAI's faster, cost-efficient GPT-5 variant for low-latency and high-volume work.

GPT Image 2

OpenAI's state-of-the-art image generation model for high-quality creation and editing with text and image inputs.

GPT Image 2 Async

ReachAPI's asynchronous GPT Image 2 workflow for task-based image generation and editing with callback-ready results.